Recently I ran into a problem.
i was getting gas and randomly the vehicle didn’t recognize the key. Anyway pushed it home cut and programmed 2 blade keys using the Autel Km100X but I can’t seem to program the original or Autel replacement fob for the proximity portion. I have a **** style ignition
Any ideas? I also own NDS 2 but it won’t connect to the BCM

 

There are several fuses involved in the iKey system. Looking at a 2006 FSM - fuses 1, 6, 18, 19 & 20 in the in-cabin fusebox (near the driver's left leg). Also fuse 71 and 78 in the IPDM. I'd look at those first because sometimes the simple answer is the one you need. (Hope so)

 

Fuses been check visually and with probe. I have the original IKey, it was working with just the proximity functions at the door but not starting the vehicle now it doesn’t work at all. Changed battery etc. I’ve ordered an OEM KBRTN001 key off eBay. Will try that.

The original oem Key wasn’t accepting the learning from the key ring nor the Autel IKEY4NS4TP.

It shouldn’t bother me as much because I can start the car with the physical key. The proximity functions were just nice to have

 

It's the iKey, right? What year? '05, '06? I think that's when it was introduced and we got unlock door and trunk request buttons. Those first couple years also had the twist **** style starter switch but it was a "press and turn" if you had the iKey in your pocket. The physical "cut" key was the backup in case the fob battery died.

So by "proximity" you mean you have the external unlock request buttons but they just stopped responding? The trunk request button too?

I'm sure you know there are two different systems involved. When you press either of the external request buttons (door or trunk) the car transits a radio signal "call" and if the iKey is within a few feet of one of the antennas, it "responds" by transmitting the registered code.

The other system is a scanner that looks for the chip molded into the plastic end of the physical key. When you insert that key into the twist ignition switch it's scanned to be sure it has the registered chip embedded in it.

So both those systems need to be registered to the car.

Sorry if you know all that. If you need the Factory Service Manuals you can go here:
https://www.nicoclub.com/infiniti-service-manuals
Scroll down, click G37/G37/Q40, click G35, click coupe or sedan, click the year... "Body, Lock and Security" is the book you want. Click that, then scroll down below the "viewing window" and you can "Click here to download a copy".

 

I'd say the BCM is on its way to retirement. Not unusual for them to 'just quit working right' in our Nissans..